The nematodes inhabiting the
“The 1986 disaster at the Chornobyl Nuclear Power Plant transformed the surrounding region into the most radioactive landscape known on the planet,” write the study authors. Almost 40 years on, a 30-kilometer (18.6-mile) region around the site remains abandoned due to high levels of lingering radiation, although it’s currently unclear how this has affected the
“Did the sudden environmental shift select for species, or even individuals within a species, that are naturally more resistant to ionizing radiation?” ponders study author Sophia Tintori in a
Because
Further analyses revealed that the nematodes from
“This doesn’t mean that Chornobyl is safe – it more likely means that nematodes are really resilient animals and can withstand extreme conditions,” says Tintori. “We also don’t know how long each of the worms we collected was in the Zone, so we can’t be sure exactly what level of exposure each worm and its ancestors received over the past four decades.”
Wondering if the nematodes from the CEZ might simply have a special mechanism for repairing damaged DNA, the researchers then exposed the animals to three different mutation-causing chemicals and observed how these mutations were passed on to future generations. Overall, they found that different nematode strains displayed different levels of tolerance to these mutagens, but that their responses could not be predicted by their exposure to radiation.
In other words, the worms from Chernobyl were not systematically better at protecting their DNA than nematodes from elsewhere, suggesting that radiation levels within the CEZ have not selected for strains with higher degrees of genetic resilience. Instead, it seems that nematodes are simply not bothered by ionizing radiation.
While these findings are obviously great news if you’re a microscopic worm, they also hold significance for humans. For instance, they could help scientists understand why some people are more susceptible to DNA damage than others, thus leading to new insights into the development of cancer and other diseases.
“Now that we know which strains of [nematode] are more sensitive or more tolerant to DNA damage, we can use these strains to study why different individuals are more likely than others to suffer the effects of carcinogens,” says Tintori.
The study is published in the